Bed knife grinder and guide means therefor



c. L. TURNER 2,863,262

Dec. 9, 1958 BED'KNIFE GRINDER AND GUIDE MEANS THEREFOR ZSheetS-Shet 1 Filed March 23, 19,56

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BED KNIFE GRINDER AND GUIDE MEANS THEREEOE Filed March 23, 195e 2 sheets-sheet 2 United States Patc-:nt Oce 2,853,262 Patented Dec. 9, 1953 BED KNIFE GRlNDER AN D GUIDE MEANS THEREFOR Charles L. Turner, Pocatello, Idaho, assignor of one-half to Marjory C. Turner, Pocatello, Idaho The present invention relates in general to grinders and,

more particularly, to a grinder for the bed knife of a Y lawn mower of the reel type.

Primary objects of the invention are to provide a grinder which is simple to operate and which will grind the upper surface and the front edge of a bed knife quickly and accurately.

An important object of the invention is to provide a grinder having guide means engageable with the bed knife for guiding the grinder along the bed knife accurately.

Another important object is to provide a grinder having means for displacing the reel during movement of the grinder along the bed knife, it thus being unnecessary with the present invention to remove the bed knife, or the reel, from the mower, which is an important feature.

Another object of the invention is to provide a grinder which includes a motor having a housing and a shaft projecting from the housing, a grinding wheel on the shaft, a frame mounted on the housing, first guide means mounted on the frame and engageable with the front edge of the bed knife for guiding the grinder along the bed knife with the grinding wheel in engagement with the upper surface of the bed knife, and second guide means mounted on the frame and engageable with the lower surface of the bed knife for guiding the grinder along the bed knife with the grinding wheel in engagement with the front edge of the bed knife. i

Another object is to provide a grinder having first reel displacing means carried by the frame and engageable with a blade of the reel to displacethe reel during movement of the grinder along the bed knife with the first guide means in engagement with the front edge of the bed knife, and having second reel displacing means mounted on the frame and engageable with a blade of the reel to" displace the reel during movement of the grinder `along the bed knife with the second guide means in engagement with the lower surface of the bed knife.

Still another object is to provide means for adjusting the positions of the two guide means and the two reel displacing means relative to the frame to accommodate bed knives of various types.

Another object is to provide means for mounting the frame on the motor housing in a simple manner, comprising a saddle adapted to seat against the motor housing, means for adjusting the saddle relative to the motor housing, and a clamping band encircling the motor housing for maintaining the saddle in seated relationship therewith.

The foregoing objects, advantages and features of the present invention, together with various other objects, advantages and features thereof which will be evident to those skilled in the art in the light of this disclosure, may be attained with the exemplary embodiment of the present invention illustrated in the accompanying drawings and described in detail hereinafter. Referring to the drawings:

Fig. 1 is a side elevational View of the grinder of the invention showing it in use to grind the upper surface of the bed knife of a reel type lawn mower;

Fig. 2 is a side elevational view of the grinder of the invention showing it in use to grind the front edge of the bed knife;

Fig. 3 is a plan view of an attachment'for converting a motor into the grinder of the invention;

Fig. 4 is a front elevational View of the attachment illustrated in Fig. 3 of the drawings. t

In the drawings, the numeral 1t) designates a conventional electric motor having a housing 12 and a projecting armature shaft 14 on which is mounted a grinding wheel 16. The motor housing 12 provides a pistol grip 18 having associated therewith a trigger switch 20 for energizing the motor. Power is supplied to the motor 10 through a cord 22.

Mounted on the lmotor housing 12 is a frame 28'which includes a saddle 30 adapted to seat on the upper surface of the motor housing adjacent the shaft end thereof. The saddle 30 is shown as including an angle member 32 having at its rearward end a cross member 34 provided with depending flanges 36. The angle member 32 is provided with bosses 38 thereon and threaded through these bosses and through the angle member are adjusting screws d@ engageable with the motor housing 10 to seat the saddle 30 on the upper surface of the motor housing properly. The saddle is maintained seated on the upper surface of the motor housing 12 by means of a clamping band 42 which encircles the motor housing and the angle member 32 of the saddle, the clamping band being welded, or otherwise secured, to the angle member. The clamping band 42 terminates beneath the motor housing i2 in ends 44 adapted to be drawn together by a bolt 46 extending therethrough.

Mounted on the frame 28 is a first guide means 50 which is located between the motor housing 12 and the grinding wheel 16 adjacent one edge or side of the grinding wheel and adjacent the rear face of the grinding wheel, i. e., the face of the grinding wheel nearest the motor housing 12. The first guide means 50 takes the form of a first guide member S2 paralleling the rear face of the grinding wheel 16 adjacent one side thereof, the guide member 52 being secured to one arm of an angle bracket S4 by a screw 56 threaded into the bracket. The other arm of the bracket 54 is connected to the lower end of a bracket 5S, as best shown in Fig. 4 of the drawings, by a screw 60 which projects through an elongated notch 62 in the bracket 58 and which is threaded into the bracket 54. A pin 64 carried by the bracket 54 is disposed in the notch 62 in the bracket 58 to prevent rotation of the bracket 54 about the axis of the screw 60. The upper end of the lbracket 58 is welded, or otherwise secured, to the angle member 32 of the saddle 30. With this construction, by loosening the screw 60, the bracket 54 may be moved upwardly or downwardly, as viewed in Fig. 4 of the drawings, to move the first guide member 52 radially inwardly or outwardly with respect to the grinding wheel 16. This adjustment varies the extent to which the upper surface of a bed knife is ground, as will be explained in more detail hereinafter.

Also mounted on the frame 28 is a second guide means 68 located adjacent the front face of the grinding wheel 16 and adjacent the opposite edge or side of the grinding wheel from the lirst guide means 50. The second guide means 68 includes a second guide member 70 paralleling the front face of the grinding wheel 16, the second guide member'forming the base of a U-shaped member having arms 72 the rearward ends of which are connected to the saddle 30 by screws 74 extending therethrough and threaded into the depending flanges 36 on the cross member 34 of the saddle, as best shown in Fig. 3 of the drawings. The radial position of the second guide member 70 relative to the grinding wheel 16 is controlled by an adjusting screw 76, Fig. 4, threaded through an arm `very convenient.

7S of the frame 23 and engageable with one of the arms 72 carrying the second guide member. As will be explained hereinafter, this radial adjustment of the second guide member controls the extent to which the grinding wheel 16 projects in grinding the front edge of abed knife.

The grinder of the invention also 'includes first reel displacing means (30 for displacing a lawn mower reel when the Yfirst guide means S is in engagement with VVthe lawn mower bed knife, as will be explained hereinafter. The first reel displacing means d@ includes fingers S2 at the ends of the first guide member 52, these fingers being located alongside the periphery of the grinding wheel 16 and projecting forwardly beyond the front face thereof slightly.

The grinder of the invention further includes a second reel displacing means 8d for displacing a lawn mower reel when the second guide means 68 is in engagement with the lawn mower bed knife, as more fully described hereinafter. The reel displacing means includes a finger 86 which is pivotally connected to a lug fifi on the frame 28 by a bolt 90. Threaded through the finger 36 is an adjusting screw 92 which engages the upper surface of the clamping band 42 to regulate the angular position of the finger relative to the frame 23 so that this finger properly 'engages a blade of the lawn mower reel.

`Referring now to Figs. l and 2 of the drawings, fragmentarily illustrated therein is a lawn mower 100 carried 'by 'supports 102 and 104 with the bed knife of the mower, designated by the numeral 106, oriented in a generally vertical plane. The bed knife 106 is provided witha front edge 108 which is uppermost with the bed knife oriented as shown, and is provided with upper and lower surfaces 110 and 112 which are substantially vertical with the bed knife oriented as illustrated. It will be understood Vthat the orientation shown for the bed knife is not essential to the present invention, but is having spiral blades 116 which cooperate with the bed knife 106 in a well known manner.

Considering the operation of the grinder of the invention, the upper surface 110 of the bed knife 106 is preferably ground first, Ias shown in Fig. l of the drawings, and then the front edge 10? thereof is ground, as shown in Fig. 2. Considering first the manner in which the upper surface 110 is ground, the grinder is applied to the bed knife 106 as shown in Fig. l of the drawings, the rst guide means 50 being adjusted radially of the grinding wheel 16 to provide the desired grinding depth from the front edge 10d. With the grinding wheel 16 positioned substantially vertically as shown, and with the first guide member 52 resting on the front edge 10? of the bed knife 106, the grinder is moved along the bed knife so that the grinding wheel grinds the upper surface 110 of the bed knife. The direction of grinder movement along the bed knife 106 depends on the direction of reel blade twist, and is preferably such that one of the fingers 82 always engages one of the reel blades 116 tocontinuously depress such reel blade out of the way of the grinding wheel, this action being automatic. Preferably, the grinder is held so that the grinding wheel 16 grinds the upper surface 110 progressively deeper in a direction away from the front edge 108 of the bed knife 106 so that, after vgrinding is completed, the reel blades 116 strike the upper surface of the bed knife just at the front edge 108 thereof. f

After the upper surface 110 of the bed knife 106 ha been ground in the foregoing manner7 thefront edge 108 thereof is ground, as will now be described. Referring to Fig. 2` of the drawings, the grinder is positioned so that the grinding wheel 16 is substantially horizontal and rests on the front edge 10S of the bed knife, the second guide member 70 being in engagement with`the lower surface 112 of the bed knife. The position of the Adjacent the bed knife is a reel 114 second guide member 70 radially of the Vgrinding 'wheel 16 may be adjusted by means of the adjusting screw '76 to cause the grinding wheel to project beyond the upper surface 110 of the bed knife so as to grind the entire edge thereof. The pivoted finger 86 of the second reel displacing means 84 is so adjusted, by means of the adjusting screw 92, that it properly engages one of the reel blades 116 'to displace the reel out of the way as the grinder is moved along the bed knife 106. These adjustments completed, the grinder is vmoved along the bed knife 166 with the second guide member 70 in engagement with the lower surface 112 thereof and with the front face of the grinding wheel 16 in engagement with the front edge 108 of the bed knife. The motion of the grinder is continued until the front edge 108 has been completely ground, the finger 86 continually displacing the reel114 out of the way. Preferably, the grinder-is'moved in one direction or the other, depending on the reel lblade twist, in such a manner that the finger S6 continuously raises the reel blade which it engages.

Thus, duringV grinding of the upper surface 110 of the bed knife 106, the rear face of the grinding wheel 16 is used and the first guide means 50 engages the front edge 108 of the bed knife to guide the grinding wheel along the upper surface thereof accurately. At the saine time, one of the fingers S2 continuously displaces the reel 114 out of the way. When grinding the front edge 108 of the bed knife 196, the front face of the grinding wheel 16 is used and the second guide means 68 slides along the lower surface 112 of the bed knife to guide the grinding Wheel accurately. At the same time,v the finger 86 continuously displaces the reel 114 out of the way. The various adjustments provided for the two guide means S0 and 68 and the two reel displacing means; and 84 adapt the grinder of the invention to any lawn mower of the reel type.

It will be apparent that the invention provides a very simple and effective grinder for dressing lawn mower bed knives, and one which may be operated without any particular skill to obtain accurate results.

Although l have disclosed an exemplary embodiment of my invention herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims hereinafter appearing.

I claim as my invention:

l. fn a grinder for the bed knife of a reel-type lawn mower, the bed knife having upper and lower surfaces and a front edge, the combination of: a motor having a housing and a shaft projecting from said housing; a grinding wheel on said shaft; a frame mounted on said housing; first guide means mounted on said frame adjacent the periphery of said grinding wheel and engageable with the front edge ofthe bed knife for guidingthe grinder along the bed knife with said grinding wheel in engagement with the upper surface of the bed knife; second guide means mounted on said frame adjacent the periphery of said grinding wheel and substantially diametrically opposite said first guide means and engageable with the lower surface of the bed knife for guiding the grin-deralong the bed knife with said grinding wheel inl engagement with the front edge of the bed knife; first reel displacing means carried by said frame adjacent said firstv guide means and engageable with a blade of the reel to displace the reel during movement of the grinder along the bed knife with said first guide means in engagement with the front edge of the bed knife, said first reel vdisplacing means including at least'one finger on said first guide means and projecting axially away from said housing and located alongside the periphery of said grinding wheel; and second reel displacing means Vmounted on said frame adjacent said second guide means and engageable with a blade of the reel to displace the reel during movement of the grinder along the bed knife placing means including a iinger pivotally connected to said frame.

2. A grinder for a lawn mower, as set forth in claim 1 including means carried by said pivoted nger of said second reel displacing means and engageable with said frame for adjusting the position of said pivoted nger relative to said frame.

3. In a grinder for a lawn mower, the combination of: a motor having a housing and a shaft projecting from said housing; a grinding wheel on said shaft; a frame mounted on said housing; rst guide means mounted on said frame adjacent said grinding wheel and second guide means mounted on said frame adjacent said grinding wheel, said second guide means including a guide member mounted on said frame by arms each connected at one end to said guide member and pivotally connected at its other end to said frame at a point adjacent said housing and spaced from said grinding wheel.

References Cited in the file of this patent UNITED STATES PATENTS 1,968,609 Madsen July 3l, 1934 2,586,236 Lewis et al Feb. 19, 1952 2,589,165 Toy et al Mar. 11, 1952 2,613,483 Lewis et al. Oct. 15, 1952 

